Carboxyalkylmercapto stibonic acid compounds



Patented Feb. 5, 1952 UNITED ISTATIEZS. PATENT OFFICE ALKYLMERCAPTO S TIBONIC acm-ioo uroonns NorbertSteigenNutley, and Oscar Keller, Clifton, N. J., assignors 1:0 Hoffmann-La Roche Inc., Nutley, N. J., acorporation of New Jersey Nonrawing- Applic uly 13, 19.48; Serial No. 38,568

6 Elaims (Cl. 260-446) The present invention relates to aryland nitroheterocyclio stibonic acids which contain as a nuc ear .C-sub uen a car xyal sylm rcapto lIQl D -,S?a1ky1 C.OQH),. and the salts thereof. flhis application is a continuation-in-part of our application Serial "No. 676,863, filed June .14, 19%, o abandoned The n w .stibonic acid can e rep esente by the io lpwiae fo mu a;

(S a Ev -S 0.011),.

isuogoro i.

. I (1) wherein z stands for an aryl or nitroheterocyclic radical and n for a small inte r, sue-has 11 o Z, for example, can represent a substituted .or u su stitut d aryl radicalsas fer-exampl ph yl. diph ny-l, naphthalene. or a zpxridxlradical, tree from 'substituents; or containin substituents such as aliphatic, halogen, ialkoxy, v carboxy, eule foxy, acyl-ami-no radicals, and the like. The compounds of Formula I can :he converted :into the corresponding ICHIIbOXYIatBYSEItSLfiS ;for example, the metal salts, such as the alkali metal and alkaline earth metal salts; and the nitrogen salts, as for example, the ammonium and organicgamine salts.

In general, he mmnounds L6; Formul :1 an be prepared zby reactin a diaz tized-amin arylor amino-nitroheterocyclic-mercaptoalkylooarantimonite- The reaction tan be illustrated "by the following equation:

Z and n in the above equation having the same boxylic acid with an antimpmtesueh as sodium significance as in Formula "I. For example, the

simplest representative of these compounds; namely, 2 carboxy methylmercaptobenzenestibonic acid can be prepared ;from Z-aminophenyl-thiog-lycol-lic'acid 'by'reacting its 18%? Z 2 eompound with antimonite according to the following equation:

.SCH2O OONa A preferredprocedure of preparing the new compounds can be illustrated by the following schematic equation: m

I (NED,- Z and n have the same significance as herein- .a'bove described.

The 2 ,mercapto e arylornitroheterocvclicthiazole (IV) is hydrolyzed with an alkali, as for characterized by their remarkable chemotherapeutic activity in trypanosomaland Leishmania donovani infections of laboratory animals. The aqueous solutions of the Water-soluble saltswhen injected subcutaneously or intravenously, are "less irritating than other stibonic acids'which -haveLbeentherapeutically-used.

The following examples will serve to illustrate t e invention:

3 EXAMPLEI Preparation of the stibonic acid derivative of phenyl-thzo-glycollic acid S-CH:O O OH Sodium salt of:

s 39 grams (0.23 mol) of the lactam of phenylthioglycollic acid were hydrolyzed by refluxing with 175 cc. 2 N NaOH (0.35 mol) for 18 hours.

The clear brown solution was diazotized by dissolving in it 18 grams (0.25 mol) NaNOz and adding the solution dropwise'to 200 grams crushed ice-[ 77 cc. concentrated HCl with stirring at 05 C. The diazotized solution was filtered through Celite (diatomaceous earth) in the cold.

The filtrate was kept cold and was slowly added .to the following mixture: grams Sb203+90 cc.

per cent NaOH+85 grams glycerine+300 grams H2O+3 grams copper dust at 15-25" C. with stirring. The reaction mixture was brought to faint tion was filtered through Celite and acidified to Congo with concentrated HCl. The resulting suspension was cooled in a refrigerator alkalinity. to phenolphthalein with concentrated I-ICl and was then saturated with C02. The solu- The separated stibonic acid compound was filtered oil. and washed with water. It was then sucked dry. The material was then dissolved in water containing about 0.5 mol (70 grams) crystalline sodium acetate (volume about 1 liter). The solution was stirred with Norite (activated .charcoal) and "Celite for 1 hours.

used for injections. It is also soluble in aqueous diethanolamine, the solution being suitable for injection. 7

The stibonic acid can be purified from any inorganic impurities by dissolving it in methanol V and subsequently precipitating it with ether.

EXANIPLE 2 320 grams of the zinc mercaptide of 2-aminoj benzenethiol are finely powdered and suspended in a mixture of 250 cc. of ethanol and 3 liters of water. In a separate vessel, 200 grams of monochloracetic acid are covered with 500 grams of crushed ice and 500 cc. of 40 per cent NaOH are added with stirring. The alkaline solutionis then added to the suspension of the zinc mercaptide of 2-amino-benzenethiol and the mixture is heated at C. for three hours with stirring.

After standing for sixteen hours, the mixture is heated to C. and is filtered with activated charcoal. The purplish filtrate is cooled to room temperature and to it is added a solution of grams of NaNO. in 400 cc. of water. The solu-' tion is slowly added under the surface to a mixture of 500 grams of ice, 500 cc. of concentrated I-ICl and 1 gram of NaNOa with stirring. The temperature. is kept between 0 and 5 C. The diazotization takes aboutfthree hours.

The diazotized solution is then rapidly filtered with activated charcoal and the cold filtrate is slowlyrun into a mixture of 240 grams of antimony trioxide, 600 cc. of 40 per cent NaOH, 1500 cc. of water; 640 grams of glycerine and 5 grams of copperdust with stirring. This takes about one hour. Stirring is continued for three hours.

Afterstandlng for about sixteen hours, concentrated HCl i added to the reaction mixture until it is barely alkaline to phenolphthalein. The solution is then saturated with CO2 gas (1 hour). The mixture is then filtered with activated charcoal. The filtrate is cooled to 10 C. and HCl is addeduntil the. solution gives purple color with Congo paper. 1 The mixture is stirred one hour in the cold and the precipitate of the crude stibonic acid is filtered off. Theprecipitate is washed with some cold water and the cake pressed dryf The cake is dissolved ina solution of 160 grams NaHCOs in 2000 cc. of water- 2 liters of water are added then and the solution is cooled to 10 C. HCl is then added slowly until a pH of 4.2-4.3.

The mixture is stirred 1 hour in the cold and the dark precipitate is filtered off. The filtrate is again cooled to 10 and HCl is added to Congo blue. After stirring for one hour in the cold, the pure light colored 2- carboxymethylmercaptobenzene-stibonic acid is filtered off, washed acid free with ice'water and is dried in vacuo.

100 grams of the stibonic acid are shaken with 350 cc. of methanol and 30 grams of anhydrous Na2SO4 for two hours. The clear brown solutions is filtered and added to 7 liters of ether with stirring. After standing'for sixteen hours in the cold, the purified stibonic acid is filtered off, washed with ether and is dried in vacuo.

Various salts of the 2-carboxymethylmercaptobenzene-stibonic acid can be prepared, as for example:

1.5 grams of the stibonic acid is stirred with 25 cc. water and 0.5 cc. diethanolamine. The filtered solution contains the diethanolamine salt.

1.5 grams of the stibonic acid is stirred with 25 cc. of water and 1 cc. diethylamine. The filtered solution contains the diethylamine salt.

1.5 grams of the stibonic acid is stirred with 25 cc. of water and 0.5 cc. triethanolamine. The filtered solution contains the triethanolamine salt.

10 grams of the stibonic acid are stirred with cc. of water and 10 grams of CaCOa for three hours. The mixture is filtered and the clear filtrate is concentrated to dryness in vacuo to obtain the calcium salt.

5 grams of the stibonic acid are stirred with 100 ccqof water and 5 grams ,of MgCOz; for two hours. The filtered solution contains the magnesium salt and has a pH of 7.9.

5 grams of the stibonic acid are stirred wit 100 cc. of water and 10 grams of BaCO; for 2 hours. The filtered solution contains the barium salt and has a pH of 5.6.

601 rams: of purified: stibor'uc. acid; are. stirred with 1000 cc.- water' and 60) gramsv (3.2.0011. for;

three hours. with nitrogen bubbling through the mixture. The filtered solution-'is'then saturated.

with nitrogen for- 40-:hours. The; solution. is then:

passed through: a. Berkfeld candle. with nitrogen bubbling through it. Additionof 10.? grams of. sarcosine anhydrid'e anddilution to-1 200 cc. gives a stable 5 per cent solution of the calcium salt. Ampules prepared from the solution-remain stable for 500hours-atx45-C.

1 -carb oxymethylmemapto-Z-naphthalenestibonic acid- 0.25 mol of the sodium salt of Z-amino-naphthalene-thioglycolic acid was dissolved in 500 cc. of water. 18 grams of sodium. nitrate were added and the solution was diazotized by addition to a mixture of 100 cc. of concentrated HCl and 100 grams of ice at to C. The diazo solution was filtered and added to a mixture of 30 grams of' antimony trioxide, 80 grams of glycerine, 100 cc. of 40 per cent NaOI-I, 2 grams of copper dust and 20000. of water. The stibonic acid was precipitated by acidification with HCl and purified by reprecipitation from dilute sodium acetate solution.

EXAMPLEA H C.SII

Zia/2S NaOgCCHnCS SCHzC OzNa mo -sb- SbOaHz HOOCCHaS SCH1COOH 0.125 mol of 2 di mercaptobenzothiazolewas converted to the amino-thiol byalkaline hydrolysis with sodium hydroxide. The thiol was isolated by treatment with zinc chloride in the form of the zinc derivative. This was condensed with 0.25 mol of chloroacetic acid in alkaline solution. The di-amino-thioglycollate thus obtained was diazotized by dissolving 18 grams of NaNOz in the solution and slowly adding it to a mixture of 60 cc. HCl, 100- grams of cuprous chloride, and 1 gram NaNOz at 0 to 5 C. The diazo solution was filtered and added to a mixture of 30 grams antimony trioxide, 80 grams of glycerine, 80 cc. of 40 per cent NaOH, 200 cc. of water and 2 grams of copper dust. After warming to 45 C. the stibonic acid was precipitated byacidification with hydrochloric acid, and purified by'reprecipitation from dilute sodium acetate solution. The sodium salt solution has a good trypanocidal activity.

2- (carbomymet hylmercapto) -py ridin0-5j-stibo 1 ic acid HiN

5-nitro-2=thi,olpyridine was prepared according to Phillips and Shapiro, Journal of the Chemical Society (London), 1942, page 584.

31.2 grams (0.2 mol) of 5-nitro-2-thiolpyridine were suspended in 300 ml. of water, and 120 grams of sodium hydrosulfite was added with stirring, keeping the temperature below 50 C. When all was in solution, it was diluted with 200 ml. of water, filtered from any impurities, and the filtrate added tov a solution of r s of zinc chloride in 150 ml. of water. There was obtained the zinc derivative of 2-thiol-5-aminopyridine as a white amorphousprecipitate. This was filtered, the filter cake sludged with water, made alkaline with 30 cc. of NaOl-I solution (40% by volume) and condensed with an alkaline solution of 20 grams of monochloracetic acid at ill-50 C. It was filtered fromimpurities. To the filtrate was added a concentrate aqueous solution of 14 grams of sodium nitrite. It was run into cc. of concentrated HCl and crushed ice below +5 C. The obtained diazc compound was added at 15 to 20 C. to a. sludge of 50 grams of SbzOs, 140 cc. of NaOH (40% by volume), 3 grams of copper powder, 120 grams of glycerine and 400 cc. of water. After disappearance of the diazo-reaction it was almost neutralized with HCl, then saturated with CO2. It was; filtered from SbzOa and acidified with HCl. There were obtained after drying about 30 grams of the stibonic acid as a light tan powder. It was soluble in NaI-ICOa or dilute diethanolamine, and formed the corresponding sodium and, diethanolamine salts.

EXAMPLE 6 Z-carbomyethylmercapto-benzene-stibonic acid 0.25 mol of the zinc mercaptide of 2-aminobenzenethiol was suspended in 250 cc. of water and 25 cc. of i0 per cent NaOH. The mixture was treated with a cold solution of, 0.25 mol ,9.- brompropionic acid containing 40 grams of sodium carbonate in 200 cc. water. The, reaction was completed by heating at 50 C. for two hours. After filtration, the solution was diazotized by dissolving 18 grams of NaNOz in the filtrate and slowly adding it to a mixture of 60 cc. of concentrated HCl and grams of ice at 0 C. to 5 C. The diazo solution was filtered and added to a mixture of 30 grams of antimony trioxide, 80 grams of glycerine, 100 cc. of 40 per cent NaOH, 2 grams of copperdust and 200 cc. of water. The stibonic acid formed was precipitated by acidification and purified by reprecipitation from dilute sodium carbonate solution.

HnOaSb SCHzC OzNa SCHaC 07H:

By using a-brompropionic acid in the same way, there is obtained 2- (a-carboxyethylmercapto) benzene-stibonic acid:

Sib 03112 The diethanolamine salts of both compounds show in solution a very distinct trypanocidal activity.

EXAMPLE '7 2-carboa:ymethylmercapt0-4-acetamidobenzene-stibonic acid.

SID OaHz NHCOCHa To a solution of 105 grams of the sodium salt of i-acetamido-2-carboxymethylmercapto aniline in 1000 cc. of water were added 32 grams of sodium nitrite. This was run under the surface of 1000 cc. of water, 500 grams of ice, 110 cc. of concentrated HCl with agitation and coolingmaintaining a temperature of C. to C. during the addition. The diazo compound was filtered and added at to C. slowly to a sludge of 30 grams of Sb203, 80 cc. of NaOH (40%), 80 grams of glycerine, 200 cc. of water, 2 grams of Cu powder. After standing overnight, it was saturated with CO2, filtered, and the filtrate acidified. The precipitated stibonic acid was filtered, washed with water, and finally dried.

EXAMPLE 8 2-carbomymethylmercapto-4-methoxybenzene-stibonic acid 40 grams of 2-mercapto-4-methoxy-aniline were condensed with grams of monochloracetic acid in a 5 per cent NaOH solution. The resulting 2-carboxymethylmercapto-4-methoxy-aniline was diazotized with 21 grams of NaNOz in the presence of 165 cc. of concentrated HCl and ice at 5 to 10 C. The diazo solution was then reacted with a mixture containing 40 grams of antimony trioxide, 100 grams of glycerine, 90 cc. of 40 per cent NaOH, 200 cc. of water and 3 grams of copper dust. The stibonic acid was precipitated by acidification with H01 and purified by precipitation from a 10 per cent sodium acetate solution.

EXAMPLE 9 2-carboarymethylmercapto-4-"nethylbcnzene-stibonic acid SCHzCOOH 45 grams of the zinc derivative of 2-amino-5- methyl-benzenethiol were condensed with 25' grams of monochloracetic acid in 500 cc. of water containing '75 cc. of 40 per cent NaOH. The'resulting 2-carboxymethylmercapto-4-methy1-aniline was diazotized with 19 grams of NaNOz in the presence of cc. of concentrated HCl and ice at 0 to +5 C. The diazo solution was reacted with a mixture containing 30 grams of antimony trioxide, cc. of 40 per cent NaOH, 80 grams of glycerine, 200 cc. of water and 2 grams of copper dust. The stibonic acid was precipitated by acidification with H01 and purified by reprecipitation from 800 cc. of 10 per cent sodium acetate solution with HCl.

EXAMPLE 10 2-carboa:ymethylmercapto-4-chlorobenzene-stibonic acid S 01120 O OH 30 grams of 2-mercapto-4-chloro-aniline were condensed with 20 grams of monochloracetic acid in 500 cc. of water containing 40 grams of NaOH. The resulting 2 carboxymethylmercapto 4 chloroaniline was diazotized with 18 grams of N-aNOz in the presence of 90 cc. of concentrated I-ICl at 0 to 5 C. The diazo solution was reacted with a mixture containing 30 grams of antimony trioxide, 80 cc. of 40 per cent NaOH, 200 cc. of water, 80 grams of glycerine and 2 grams of copper dust. The stibonic acid was precipitated by acidification with concentrated HCl and purified by reprecipitation from 500 cc. of 10 per cent sodium acetate solution with HCl.

EXAMPLE 11 3-carboxymethylmercapto-benzene-stibonic acid Sb O 3112 31 grams of 3-carboxymethyl-mercapto-aniline were dissolved in 40 cc. of concentrated HCl and 300 cc. of water. The solution was chilled to 0 0., and diazotized with a solution of 12.5 grams of NaNOz in 50 cc. of water at a temperature of between 0 to +15 C. The diazo compound was dropped into a slurry consisting of 22 grams of SbzOs, 60 cc. of NaOH (40% by volume), cc. of water, 1.6 grams of copper powder, 64 grams of glycerine at 15 to 25 C. After six hours stirring, the reaction mixture was neutralized with 4 cc. of concentrated HCl then saturated with carbon dioxide, and filtered. Upon acidification of the filtrate with hydrochloric acid the new stibonic acid was obtained. It was purified by redissolving at room temperature in a dilute aqueous NaHCOs solution, filtration and acidification with HCl. The 3-carboxyinethy1-mercapto-benzene-stibonic acid was obtained as a light tan powder after drying at room tempera ture in vacuo.

A solution of the stibonic acid in dilute diethanolamine shows high activity in trypanocidal infections of animals.

By using the 4-carboxymethy1mercapto-aniline as a starting material, there was obtained the 4-carboxymethylmercapto-benzene-stibonic acid, which also shows good trypanocidal activity.

EXAMPLE 12 4-carbo.r1/-2-carboxymethylmercapto-benzenestibonic acid sboam SCHRC O OH 23 grams of the zinc derivative of 2-amino-5- carboxy-benzenethiol were condensed with 10 grams of monochloracetic acid in a 12 per cent NaOH solution. The resulting 2-carboxymethylmercapto-4-carboxy-ani1ine was diazotized with 10 grams of NaNOz in the presence of 60 cc. of concentrated HCl and ice at to C. The diazo solution was then reacted with a mixture containing 15 grams of antimony trioxide, 50 cc. of 40 per cent NaOH, 1 gram of copper dust, 35 grams of glycerine and 100 cc. of water. The desired compound was precipitated by acidification with HCl and reprecipitated from 300 cc. of a 10 per cent sodium acetate solution with HCl.

In a manner similar to that described in the above examples, other stibonic acids of Formula I can be prepared. Thus there has also been prepared the following stibonic acids which can be represented by the following formulae:

SCH C O OH 8 OnNH:

@somooon Sb OaHr I O-somcoon o-scmo OOH Sb 0 aHz (f) Sb OaHR -SCH2CO2H C H: C 02H (0) Ho momsQ-s @Osomc 0,11

11,0386 Sb 03H: (h)

Sb OaH:

-CHI

CHzC 02H (0 51b 03H: 9-0 H: C H: C 0 2H (ID We claim 1. A phenyl stibonic acid having as a nuclear C-substituent a carboxyalkylmercapto group and the salts thereof.

2. 2 carboxymethylmercapto-benzene-stibonic acid.

3. 2 car'boxymethylmercapto-benzene-sodium stibonate.

4. 2 carboxymethylmercapto-benzene-calcium stibonate.

5. A compound as in claim 1, wherein the carboxyalkylmercapto group is in ortho position to the stibonic radical.

6. The diethanolamine salt of 2-carboxymethylmercapto-.benzene-stibonic acid.

NORBERT STEIGER. OSCAR KELLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,185,972 Bockmuhl et a1 Jan. 2, 1940 FOREIGN PATENTS Number Country Date 216,270 Germany Oct. 9, 1908 484,101 Great Britain May 2, 1938 OTHER REFERENCES Broshmachari: Indian Jour. Med. Res. 10, 510 (1922-1923).

Sidwick: Organic Chemistry of Nitrogen, page 522 (1944 edition). 

1. A PHENYL STIBONIC ACID HAVING AS A NUCLEAR C-SUBSTITUENT A CARBOXYALKYLMERCAPTO GROUP AND THE SALTS THEREOF. 